The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 08-20-2015, 02:08 PM   #1
ixei
Registered User
 
Join Date: Aug 2015
Location: Bellevue WA
Posts: 23
Don't mind me too much... Just a newbie carb question...

Engine in question is a 396 with an edelbrock intake manifold and carb that has an electric choke.

I've read for hours now on proper technique.
Issue is that on a cold start or most starts that she turns over then dies slowly within 5 seconds.

I currently with key off push pedal to floor once.
Let off completely and turn the key to start.

I can keep it alive if I physically keep gas with the pedal but idle drops off and dies if I let off.
I'm sensing no fast idle.

It will continue to do this if I just drive at every stop until at operating temp.

Where do I begin?
And thank yall
ixei is offline   Reply With Quote
Old 08-20-2015, 03:57 PM   #2
Jurassic-1
Registered User
 
Jurassic-1's Avatar
 
Join Date: Jul 2007
Location: New River Arizona
Posts: 1,180
Re: Don't mind me too much... Just a newbie carb question...

What type of carb do you have. If it is a Quadra jet it will have a flat headed adjustment screw on the passenger side just below the choke assy. This screw can be turned in to speed up fast idle. Edelbrock carbs are similar. You should also check your timing and dwell if it is a points type distributor.
Jurassic-1 is offline   Reply With Quote
Old 08-20-2015, 04:03 PM   #3
ixei
Registered User
 
Join Date: Aug 2015
Location: Bellevue WA
Posts: 23
Re: Don't mind me too much... Just a newbie carb question...

Quote:
Originally Posted by Jurassic-1 View Post
What type of carb do you have. If it is a Quadra jet it will have a flat headed adjustment screw on the passenger side just below the choke assy. This screw can be turned in to speed up fast idle. Edelbrock carbs are similar. You should also check your timing and dwell if it is a points type distributor.
Much appreciated. I'll take a few pictures of the carb to further help someone help me.
ixei is offline   Reply With Quote
Old 08-20-2015, 04:10 PM   #4
Wrenchbender Ret
Registered User
 
Join Date: Oct 2005
Location: Overland Park, Ks.
Posts: 5,229
Re: Don't mind me too much... Just a newbie carb question...

I have some ideas also but a photo or carb model will help.
Wrenchbender Ret is offline   Reply With Quote
Old 08-20-2015, 04:34 PM   #5
ixei
Registered User
 
Join Date: Aug 2015
Location: Bellevue WA
Posts: 23
Re: Don't mind me too much... Just a newbie carb question...

Quote:
Originally Posted by Wrenchbender Ret View Post
I have some ideas also but a photo or carb model will help.
Album of photos here : https://imgur.com/a/dLHaA

Apparently she's a Rochester Quadrojet.

In the last photo of the album it looks like that goldish arm isn't connected?
ixei is offline   Reply With Quote
Old 08-21-2015, 12:04 PM   #6
ixei
Registered User
 
Join Date: Aug 2015
Location: Bellevue WA
Posts: 23
Re: Don't mind me too much... Just a newbie carb question...

Now knowing it's a quadrajet I upped the fast idle, and marginally raised the base idle.

Seemed like she was happier.

Now to fix all the cracked vacuum caps, etc.

Should my brake booster be straight lined to the passenger valve cover? Seems like that may explain my poor braking experience.
ixei is offline   Reply With Quote
Old 08-21-2015, 12:28 PM   #7
leftybass209
Registered User
 
leftybass209's Avatar
 
Join Date: Feb 2011
Location: Modesto, CA
Posts: 2,194
Re: Don't mind me too much... Just a newbie carb question...

Your brake booster should be connected to vacuum, which can be from the rear of that edelbrock manifold behind the carb. It should never be connected to the valve cover.
leftybass209 is offline   Reply With Quote
Old 08-21-2015, 12:30 PM   #8
ixei
Registered User
 
Join Date: Aug 2015
Location: Bellevue WA
Posts: 23
Re: Don't mind me too much... Just a newbie carb question...

Quote:
Originally Posted by leftybass209 View Post
Your brake booster should be connected to vacuum, which can be from the rear of that edelbrock manifold behind the carb. It should never be connected to the valve cover.
I'll have to change that over.
She didn't start this morning, think she needs a new battery.
ixei is offline   Reply With Quote
Old 08-21-2015, 04:23 PM   #9
Wrenchbender Ret
Registered User
 
Join Date: Oct 2005
Location: Overland Park, Ks.
Posts: 5,229
Re: Don't mind me too much... Just a newbie carb question...

I can see in the photo that the choke is closed. When you start the engine the vacuum chamber plunger should go in & pull the choke about half way open. As the electric choke warms up the choke plate should open all the way & fall off fast idle. The idle mixture can be adjusted by jets inside the holes in front part of the lower housing. They take a special tool. Some are a small double D. Some are a hex. Open each jet about 1 turn & with engine warm & idle ing slowly turn each one in till the engine starts to slow down. Then turn it out till it speeds back up, about 1/2 turn.
Let us know if you have any more questions.
George
Wrenchbender Ret is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 06:03 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2026, vBulletin Solutions Inc.
Copyright 1997-2025 67-72chevytrucks.com